Minor correction: I believe it is spelled "goby," not "gobi", and "blenny", not "blennie." Also the Mandarin "Gobi" in the wishlist is actually a Mandarin Dragonet -- not a member of the goby family, though fish stores still refer to them as gobies.
I agree a purple firefish would be cool. It would have to flick that dorsal fin just right, though, and would have to have a hole or cave that it can dash into when bigger fish come around or it's chased.